Mannans are mannose containing polysaccharides found in various plants. Mannans are poorly soluble in aqueous environment and their physicochemical properties give rise to viscous dispersions. Additionally, mannans have high water binding capacity. All of these characteristics cause problems in several industries including brewing, baking, animal nutrition, and laundry and cleaning applications.
In plant-based diets different β-mannans are present and depending on their amounts and properties they can compromise nutrient digestion, microbial colonisation and growth performance. Enzymatic degradation of mannans reduces digesta viscosity of high water soluble mannans and leads to production of manno-oligosaccharides that may form water-insoluble linear mannans present in leguminoseae. Mannanase increases average daily gain, feed efficiency, weight uniformity and livability in all monogastric animals.
For animal feed applications, such as feed for monogastric animals with cereal diets, mannan is a contributing factor to viscosity of gut contents and it thereby adversely affects the feed digestibility and animal growth rate. For ruminants, mannan represents a substantial component of fiber intake and a more complete digestion of mannan would facilitate higher feed conversion efficiencies.
For laundry and cleaning applications enzyme compositions comprising mannanase can be used to degrade mannan. However, providing mannanases that are stable in varying storage and use conditions while still showing good mannan degrading activity is difficult.
Stability of industrial enzymes is an important property because the enzymes are often used in conditions that are very different from the natural environment of the enzymes. It is often that a wild type enzyme showing good performance in initial tests is not suitable for production in industrial scale, or is unstable in typical application or storage conditions.
N-linked glycosylation of proteins is a type of post-translational modification where a sugar molecule oligosaccharide known as glycan is attached to an amide nitrogen group of an asparagine (Asn, N) residue of a protein. This type of linkage is important for both the structure and function of enzymes and other proteins.
It is an object of the present invention to provide variants of mannanase having improved stability and exhibiting mannanase activity when applied in different industrial processes, as well as enzyme compositions for mannan degradation or modification.